Thin-Film Transistor and Manufacturing Method Thereof, Array Substrate and Manufacturing Method Thereof, and Display Apparatus

ABSTRACT

A thin-film transistor and a manufacturing method thereof, an array substrate and a manufacturing method thereof, and a display apparatus are provided. The method for manufacturing the TFT includes: forming a gate electrode, a gate insulating layer, a metal oxide semiconductor active layer, a source electrode and a drain electrode on a substrate; the forming the metal oxide semiconductor active layer includes: forming the metal oxide semiconductor active layer by electrochemical reaction. The method for manufacturing the TFT is applied in the production of the TFT and the array substrate and the display apparatus comprising the TFTs and provides a new method for forming the metal oxide semiconductor active layer.

TECHNICAL FIELD

Embodiments of the present invention relate to a thin-film transistor(TFT) and a manufacturing method thereof, an array substrate and amanufacturing method thereof, and a display apparatus.

BACKGROUND

In recent years, with the rapid development of display technology, earlycathode ray tube (CRT) display has also been replaced by active-matrixdisplay, e.g., active-matrix liquid crystal display (AMLCD) andactive-matrix organic light-emitting diode (AMOLED) display. In theseactive-matrix displays, TFT, taken as a core device of active-matrixdisplay technology, receives great attention and is widely applied.

According to different materials of active layers in TFTs, the TFTs maybe divided into amorphous silicon (a-Si) TFT, polysilicon (poly-Si) TFT,metal oxide TFT, etc. The metal oxide TFT and the poly-Si TFT havehigher mobility than the a-Si TFT. Compared with the poly-Si TFT, themanufacturing process of the metal oxide TFT is simpler as there is nolimit on devices for ion implantation and laser crystallization.Therefore, the metal oxide TFT is widely applied in liquid crystaldisplays (LCDs), organic light-emitting diode (OLED) displays andpolymer light-emitting diode (PLED) displays.

SUMMARY

Embodiments of the present invention provide a TFT and a manufacturingmethod thereof, an array substrate and a manufacturing method thereof,and a display apparatus, so as to provide a new method for manufacturinga metal oxide semiconductor active layer.

In one aspect, at least one embodiment of the present invention providesa method for manufacturing a TFT. The method comprises a step of forminga gate electrode, a gate insulating layer, a metal oxide semiconductoractive layer, a source electrode and a drain electrode on a substrate.In the method, forming of the metal oxide semiconductor active layerincludes: forming the metal oxide semiconductor active layer byelectrochemical reaction.

In another aspect, at least one embodiment of the present inventionprovides a TFT, which comprises a gate electrode, a gate insulatinglayer, a metal oxide semiconductor active layer, a source electrode anda drain electrode. In the TFT, the metal oxide semiconductor activelayer is formed by electrochemical reaction.

In still another aspect, at least one embodiment of the presentinvention provides an array substrate, which comprises the foregoingTFT.

In still another aspect, at least one embodiment of the presentinvention provides a method for manufacturing an array substrate, whichcomprises a step of forming a TFT on a substrate. A method for formingthe TFT is the foregoing method for manufacturing the TFT.

In still another aspect, at least one embodiment of the presentinvention provides a display apparatus, which comprises the foregoingarray substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

Simple description will be given below to the accompanying drawings ofthe embodiments to provide a more clear understanding of the technicalproposals of the embodiments of the present invention. Obviously, thedrawings described below only involve some embodiments of the presentinvention but are not intended to limit the present invention.

FIG. 1a is a schematic structural view 1 of a TFT provided by anembodiment of the present invention.

FIG. 1b is a schematic structural view 2 of the TFT provided by anembodiment of the present invention.

FIG. 1c is a schematic structural view 3 of the TFT provided by anembodiment of the present invention.

FIGS. 2a to 2e are schematic diagrams illustrating the process offorming the metal oxide semiconductor active layer, the source electrodeand the drain electrode, in the method provided by an embodiment of thepresent invention.

FIG. 3 is a schematic structural view 1 of an array substrate providedby an embodiment of the present invention.

FIG. 4 is a schematic structural view 2 of the array substrate providedby an embodiment of the present invention.

FIG. 5 is a schematic structural view 3 of the array substrate providedby an embodiment of the present invention.

REFERENCE NUMERALS OF THE ACCOMPANYING DRAWINGS

-   10—Substrate; 20—Gate Electrode; 30—Gate Insulating Layer; 401—First    Pattern; 402—Metal Oxide Semiconductor Active Layer; 501—Source    Electrode; 502—Drain electrode; 45—Cu Metal Film; 60—Photoresist;    601—Photoresist-completely-retained portions;    602—Photoresist-semi-retained Portion;    603—Photoresist-completely-removed portions; 70—Half-tone Mask;    701—Completely Opaque Portion; 702—Semitransparent Portion;    703—Completely Transparent Portion; 801—Pixel Electrode; 802—Common    Electrode; 901—Anode; 902—Organic Material Function Layer;    903—Cathode.

DETAILED DESCRIPTION

For more clear understanding of the objectives, technical proposals andadvantages of the embodiments of the present invention, clear andcomplete description will be given below to the technical proposals ofthe embodiments of the present invention with reference to theaccompanying drawings of the embodiments of the present invention.Obviously, the preferred embodiments are only partial embodiments of thepresent invention but not all the embodiments. All the other embodimentsobtained by those skilled in the art without creative efforts on thebasis of the embodiments of the present invention illustrated shall fallwithin the scope of protection of the present invention.

In the study, the inventors of the application have noted that:currently, the method for forming the metal oxide semiconductor activelayer in the metal oxide TFT includes coating a metal oxidesemiconductor film on a substrate, etching the metal oxide semiconductorfilm in the region other than an active region by a patterning process,to form the metal oxide semiconductor active layer disposed in theactive region. Therefore, the forming method is relatively simple.

The embodiment of the present invention provides a method formanufacturing a TFT. The method comprises: forming a gate electrode, agate insulating layer, a metal oxide semiconductor active layer, asource electrode and a drain electrode on a substrate. Moreover, thestep of forming the metal oxide semiconductor active layer includes:forming the metal oxide semiconductor active layer by electrochemicalreaction. In the method for manufacturing the TFT provided by theembodiment of the present invention, the substrate is taken as a base,does not belong to a structure of the TFT, may be a base substrate notprovided with any other structure, and may also be a substrate providedwith some layer structures. Of course, the substrate may also be asubstrate of any material or shape. No limitation will be given in theembodiment of the present invention.

It should be noted that: firstly, for instance, a bottom-gate TFT asshown in FIGS. 1a and 1c and a top-gate TFT as shown in FIG. 1b may bemanufactured by the above manufacturing method. But the embodiment ofthe present invention is not limited thereto, as long as a metal oxidesemiconductor active layer 402 in the TFT can be formed byelectrochemical reaction.

In the embodiment of the present invention, the relative positions ofthe metal oxide semiconductor active layer 402, a source electrode 501and a drain electrode 502 are not limited. The metal oxide semiconductoractive layer 402, the source electrode 501 and the drain electrode 502may be arranged in the same layer and may also be arranged in differentlayers.

Secondly, the process of the electrochemical reaction and the materialof the active region before the electrochemical reaction are notlimited, as long as the metal oxide semiconductor active layer 402 canbe formed in the active region by electrochemical reaction.

The embodiment of the present invention provides a method formanufacturing a TFT. The method comprises: forming a gate electrode 20,a gate insulating layer 30, a metal oxide semiconductor active layer402, a source electrode 501 and a drain electrode 502 on a substrate 10.In the method, the metal oxide semiconductor active layer 402 is formedby electrochemical reaction. Compared with the way of coating the metaloxide semiconductor film on the substrate, etching the metal oxidesemiconductor film in the region other than the active region by apatterning process, to form the metal oxide semiconductor active layerdisposed in the active region, the embodiment of the present inventionprovides a new method for manufacturing the metal oxide semiconductoractive layer 402.

For instance, the metal oxide semiconductor active layer is of a Cu₂Osemiconductor material.

In general, when Cu metal is diffused into an a-Si or poly-Sisemiconductor layer, semiconductor material may change into a conductor,or the performances of the semiconductor layer may also be affected eventhe semiconductor material does not reach the mobility of a conductor.In an embodiment of the present invention, as the metal oxidesemiconductor active layer 402 is of Cu₂O, even though a electrodematerial (e.g., the material of the source electrode and the drainelectrode) adopts Cu metal, when Cu₂O and Cu metal contact, balance maybe formed between Cu₂O and the diffusion of Cu, and hence a stableperformance of the semiconductor layer can be guaranteed. That is tosay, the metal oxide semiconductor active layer 402 will not besensitive to the diffusion effect of the Cu metal.

Moreover, considering that the Cu metal has large reserve volume innature and is relatively cheap, thus, for instance, the metal oxidesemiconductor active layer 402 of a Cu₂O semiconductor material isformed by the electrochemical reaction on Cu metallic material.

On this basis, a first pattern of a Cu metallic material may be formedin the active region at first; subsequently the Cu metallic material isconverted into Cu₂O semiconductor material by electrochemical reaction;and hence the metal oxide semiconductor active layer 402 is formed bythe first pattern. That is to say, in at least one embodiment, the stepof forming the metal oxide semiconductor active layer may include:forming a metal film on the substrate; forming the first patterndisposed in the active region by performing one patterning process onthe metal film; and forming the first pattern into the metal oxidesemiconductor active layer by the electrochemical reaction. Theembodiment of the present invention is only illustrated by taking thecase that the metal oxide semiconductor active layer 402 of the Cu₂Osemiconductor material is formed by the electrochemical reaction on theCu metallic material as an example, but is not limited thereto.

Of course, the step of forming the metal oxide semiconductor activelayer may also include: forming a film of a metallic material on thesubstrate; converting the film of the metallic material into a film ofthe metal oxide semiconductor material by the electrochemical reaction;and removing the film of the metal oxide semiconductor material in theregion other than the active region by a patterning process to form themetal oxide semiconductor active layer in the active region. Forinstance, a film of a Cu metallic material may be formed on thesubstrate at first; then, the film of the Cu metallic material isconverted into a film of a Cu₂O semiconductor material byelectrochemical reaction; and then, the film of the Cu₂O semiconductormaterial in the region other than the active region is removed by apatterning process, and hence the metal oxide semiconductor active layer402 is formed in the active region.

Based on the above two implementation modes, compared with the secondway of converting the entire film of the Cu metallic material into thefilm of the Cu₂O semiconductor material at first and then removing thefilm of the Cu₂O semiconductor material in the region other than theactive region, the first mode is simpler. Therefore, the step of formingthe metal oxide semiconductor active layer 402 of the Cu₂O semiconductormaterial by the electrochemical reaction on the Cu metallic material,for instance, may be implemented by the following means: placing asubstrate provided with a first pattern of the Cu metallic material inwater and electrifying the first pattern, whereby the Cu metallicmaterial is subjected to electrolytic reaction with the water to formthe Cu₂O semiconductor material, and the first pattern is formed intothe metal oxide semiconductor active layer 402.

For instance, the manufacturing method further comprises: before thestep of placing the substrate provided with the first pattern intowater, forming the first pattern of the Cu metallic material in theactive region by a patterning process.

Herein, as O elements have superior diffusion performance andspontaneous reaction characteristic in Cu, all of the Cu of the firstpattern disposed in the active region may be converted into the Cu₂Osemiconductor material; and after all of the Cu in the active region isconverted into Cu₂O, the current will be automatically turned off, andthe electrolytic reaction process is ended.

It should be noted that: as the process of forming the first patterninto the metal oxide semiconductor active layer 402 is only to convertthe Cu metallic material in the first pattern into the Cu₂Osemiconductor material, the first pattern and the metal oxidesemiconductor active layer 402 are only different in material and aresame in structure.

For instance, a pattern of the source electrode 501, a pattern of thedrain electrode 502 and the first pattern which are arranged in the samelayer are formed by a single patterning process.

Herein, after the first pattern is formed, as the process of forming themetal oxide semiconductor active layer 402 by the first pattern onlyneeds the electrochemical reaction, the step of forming the pattern ofthe source electrode 501, the pattern of the drain electrode 502 and thefirst pattern by a single patterning process is namely that the sourceelectrode 501, the drain electrode 502 and the metal oxide semiconductoractive layer 402 are formed by a single patterning process. Therefore,compared with the way of forming the source electrode 501, the drainelectrode 502 and the metal oxide semiconductor active layer 402 by twopatterning processes, the embodiment of the present invention reducesthe number of the patterning processes.

On this basis, compared with the way of additionally forming an etchbarrier layer in order to avoid the influence on the metal oxidesemiconductor active layer 402 when the source electrode 501 and thedrain electrode 502 are etched, in embodiments of the present invention,as the first pattern for forming the metal oxide semiconductor activelayer 402, the pattern of the source electrode 501 and the pattern ofthe drain electrode 502 are formed at the same time, the etch barrierlayer is not required to be formed, and hence the number of thepatterning processes can be further reduced. In addition, in the way offorming the etch barrier layer, as the source electrode 501 and thedrain electrode 502 must be connected with the metal oxide semiconductoractive layer 402, the etch barrier layer includes a first through holethrough which the source electrode 501 and the metal oxide semiconductoractive layer 402 are connected and a second through hole through whichthe drain electrode 502 and the metal oxide semiconductor active layer402 are connected. Moreover, the first through hole and the secondthrough hole cannot be too close in distance, thus the size of the TFTis limited. As the embodiment of the present invention has no limit inthis aspect, the size of the TFT can be reduced, and hence the demand onhigh pixels per inch (PPI) can be satisfied.

Moreover, the step of forming the pattern of the source electrode 501,the pattern of the drain electrode 502 and the first pattern, arrangedin the same layer, by a single patterning process, for instance, may beimplemented by the following process: forming a Cu metal film on thesubstrate; and forming the pattern of the source electrode 501, thepattern of the drain electrode 502 and the first pattern disposed in theactive region by performing a half-tone mask process on the Cu metalfilm. In the step, other patterns formed by the Cu metal film, exceptthe first pattern, are covered by photoresist before electrochemicalreaction is carried out.

For instance, the step of forming the pattern of the source electrode501, the pattern of the drain electrode 502 and the first patterndisposed in the active region by performing a half-tone mask process onthe Cu metal film may be implemented by the following steps S01 to S04.The steps will be described below in detail.

S01: as illustrated in FIG. 2a , forming photoresist 60 on a substrateprovided with a Cu metal film 45.

S02: as illustrated in FIG. 2b , forming photoresist-completely-retainedportions 601, a photoresist-semi-retained portion 602 andphotoresist-completely-removed portions 603 on the substrate obtainedafter the step S01 by performing exposure and development on thesubstrate provided with the photoresist via a half-tone mask 70 or agray-tone mask. The photoresist-completely-retained portions 601correspond to regions of the pattern of the source electrode 501 and thepattern of the drain electrode 502 to be formed; thephotoresist-semi-retained portion 602 corresponds to the active region;and the photoresist-completely-removed portions 603 correspond toregions that are not to be provided with Cu metal patterns and otherregions except the active region and the regions of the pattern of thesource electrode 501 and the pattern of the drain electrode 502 to beformed.

As illustrated in FIG. 2b , the half-tone mask 70 includes completelyopaque portions 701, a semitransparent portion 702 and completelytransparent portions 703. For instance, the half-tone mask 70 refers tothat: an opaque light-shielding metal layer is formed in some regions ona transparent base material; a semitransparent light-shielding metallayer is formed in some other regions; and no light-shielding metallayer is formed in other regions. The thickness of the semitransparentlight-shielding metal layer is less than that of the completely opaquelight-shielding metal layer. In addition, the transmittance of thesemitransparent light-shielding metal layer with respect to, forinstance, ultraviolet light, may be changed by the adjustment of thethickness of the semitransparent light-shielding metal layer.

On this basis, the working principle of the half-tone mask 70 isdescribed below: the intensity of transmitted light exposed in differentregions is different by controlling the thickness of the light-shieldingmetal layer in different regions on the half-tone mask 70, so that afterthe photoresist 60 is subjected to selective exposure and development,the photoresist-completely-retained portions 601, thephotoresist-semi-retained portion 602 and thephotoresist-completely-removed portions 603 respectively correspondingto the completely opaque portions 701, the semitransparent portion 702and the completely transparent portions 703 of the half-tone mask 70 areformed.

The principle of the gray-tone mask is similar to the principle of thehalf-tone mask 70.

The embodiment of the present invention is illustrated by taking all thephotoresist 60 as positive photoresist.

S03: as illustrated in FIG. 2c , forming the pattern of the sourceelectrode 501, the pattern of the drain electrode 502 and the firstpattern 401 disposed in the active region on the substrate obtainedafter the step S02 by removing the Cu metal film corresponding to thephotoresist-completely-removed portions 603 by an etching process.

S04: as illustrated in FIG. 2d , removing the photoresist correspondingto the photoresist-semi-retained portion 602 on the substrate obtainedafter the step S03 by an ashing process.

On the basis of the steps S01 to S04, the substrate obtained after thestep S04 is placed in water and electrified, so that the exposed Cumetallic material in the first pattern 401 are subjected to electrolyticreaction with water to form the Cu₂O semiconductor material, and hencethe first pattern 401 is formed into the metal oxide semiconductoractive layer 402. Moreover, after the photoresist in thephotoresist-completely-retained portions 601 is removed, the structureas shown in FIG. 2e , in which the source electrode 501, the drainelectrode 502 and the metal oxide semiconductor active layer 402 arearranged in the same layer, is obtained.

It should be noted that: FIGS. 2a to 2d only illustrate the process offorming the source electrode 501, the drain electrode 502 and the metaloxide semiconductor active layer 402; and as for the TFT, as illustratedin FIG. 1a , the gate electrode 20 and the gate insulating layer 30 maybe formed on the substrate 10 before the source electrode 501, the drainelectrode 502 and the metal oxide semiconductor active layer 402 areformed. Of course, as illustrated in FIG. 1b , the gate electrode 20 andthe gate insulating layer 30 may be formed after the source electrode501, the drain electrode 502 and the metal oxide semiconductor activelayer 402 are formed. No limitation will be given here.

Based on the above, when Cu₂O of the metal oxide semiconductor activelayer 402 is formed by the electrochemical reaction on Cu, for instance,the gate insulating layer 30 at least includes a TiO₂ and/or Al₂O₃ layerin contact with the metal oxide semiconductor active layer 402.

As TiO₂ or Al₂O₃ can be well bonded with Cu metal, the TiO₂ or Al₂O₃layer is arranged on, for instance, the upmost layer of the gateinsulating layer 30, so that the subsequently formed Cu metal film canbe well bonded with the substrate, and hence the formed metal oxidesemiconductor active layer 402 of the Cu₂O material has more stableperformance.

The embodiment of the present invention further provides a method formanufacturing an array substrate, which comprises the foregoing methodfor manufacturing the TFT.

For instance, the array substrate provided by the embodiment of thepresent invention may be an array substrate of an LCD. In this case, themethod for manufacturing the array substrate may further comprise:forming pixel electrodes 801 electrically connected with the drainelectrodes 502 as shown in FIG. 3.

Moreover, the array substrate provided by the embodiment of the presentinvention is applicable for the production of advanced super dimensionalswitching (ADS) LCD devices. The core technical characteristic of theADS technology is that: multi-dimensional electric fields are formed byelectric fields produced at edges of slit electrodes in the same planeand electric fields produced between a slit electrode layer and a plateelectrode layer, so that all of the aligned liquid crystal moleculesbetween slit electrodes and over electrodes in a liquid crystal cell canrotate, and hence the working efficiency of the liquid crystals and thetransmittance can be improved. The ADS technology can improve the imagequality of thin-film transistor liquid crystal display (TFT-LCD)products and has the advantages of high resolution, high transmittance,low power consumption, wide viewing angle, high aperture opening ratio,low color difference, no Push Mura, etc.

Therefore, for instance, the method for manufacturing the arraysubstrate may further comprise: forming common electrodes 802 and apassivation layer as shown in FIG. 4.

Of course, the array substrate provided by the embodiment of the presentinvention may also be an array substrate of an OLED display. In thiscase, for instance, the method for manufacturing the array substrate mayfurther comprise: forming an anode 901 electrically connected with thedrain electrode 502, an organic material function layer 902 disposed onthe anode 901, and a cathode 903 disposed on the organic materialfunction layer 902, as shown in FIG. 5.

For instance, the organic material function layer 902 may include: ahole transport layer (HTL), an emission layer (EML) and an electrontransport layer (ETL). For instance, in order to improve the efficiencyof injecting electrons and holes into the EML, the organic materialfunction layer may further include an electron injection layer (EIL)disposed between the cathode 903 and the ETL and a hole injection layer(HIL) disposed between the anode 901 and the HTL.

According to different materials of the anode 901 and the cathode 903,single-sided emission type array substrates and double-sided emissiontype array substrates may be divided. That is to say, when one of theanode 901 and the cathode 903 is of an opaque or semitransparentmaterial, the array substrate is single-sided emission type; and whenboth the anode 901 and the cathode 903 are of a transparent materialand/or semitransparent material, the array substrate is double-sidedemission type.

As for the single-sided emission type array substrate, top-emission typeand bottom-emission type may also be divided according to differentmaterials of the anode 901 and the cathode 903. For instance, when theanode 901 is formed close to the base substrate 10, the cathode 903being formed away from the base substrate 10, the anode 901 being of atransparent conductive material, and the cathode 903 being of an opaqueconductive material, as light is emitted from the anode 901 and exitsfrom one side of the base substrate 10, the array substrate may bereferred to as bottom-emission type; and when the anode 901 is of anopaque conductive material and the cathode 903 is of a transparent orsemitransparent conductive material, as light is emitted from one sideof the cathode 903 and exits in a direction away from the base substrate10, the array substrate may be referred to as top-emission type. Ofcourse, the relative positions of the anode 901 and the cathode 903 mayalso be replaced. No further description will be given here.

As for the double-sided emission type array substrate, for instance,when the anode 901 is formed close to the base substrate 10, the cathode903 being formed away from the base substrate 10, and both the anode 901and the cathode 903 being of a transparent conductive and/orsemitransparent material, as light is emitted from the anode 901 andexits from one side of the base substrate 10 on one hand and emittedfrom one side of the cathode 903 and exits in a direction away from thebase substrate 10 on the other hand, the array substrate may be referredto as double-sided emission type. Herein, it is also applicable if theanode 901 is formed away from the base substrate 10 and the cathode 903is formed close to the base substrate 10.

The embodiment of the present invention further provides a TFT. Asillustrated in FIGS. 1a, 1b and 1c , the TFT comprises a gate electrode20, a gate insulating layer 30, a metal oxide semiconductor active layer402, a source electrode 501 and a drain electrode 502. The metal oxidesemiconductor active layer 402 is formed by electrochemical reaction.

It should be noted that: firstly, the type of the TFT is not limited inthe embodiment of the present invention, and the TFT may be bottom-gatetype and may also be top-gate type.

Secondly, the relative positions of the metal oxide semiconductor activelayer 402, the source electrode 501 and the drain electrode 502 are notlimited, and the metal oxide semiconductor active layer 402, the sourceelectrode 501 and the drain electrode 502 may be arranged in the samelayer and may also be arranged in different layers.

Thirdly, the process of the electrochemical reaction and the material ofthe active region before electrochemical reaction are not limited, aslong as the metal oxide semiconductor active layer 402 can be formed inthe active region by electrochemical reaction.

Fourthly, in some embodiments, the TFT may comprise a substrate 10 and agate electrode 20, a gate insulating layer 30, a metal oxidesemiconductor active layer 402, a source electrode 501 and a drainelectrode 502 arranged on the substrate 10. The substrate may be a basesubstrate not provided with any other structure and may also be asubstrate provided with some layer structures.

The embodiment of the present invention provides a TFT, which comprisesa gate electrode 20, a gate insulating layer 30, a metal oxidesemiconductor active layer 402, a source electrode 501 and a drainelectrode 502. The metal oxide semiconductor active layer 402 is formedby electrochemical reaction. Compared with the mode of coating the metaloxide semiconductor film on the substrate, the embodiment of the presentinvention provides a new method for manufacturing the metal oxidesemiconductor active layer 402, wherein the method comprises etching themetal oxide semiconductor film in the regions other than the activeregion by a patterning process, to form the metal oxide semiconductoractive layer disposed in the active region.

For instance, the metal oxide semiconductor active layer 402 is Cu₂Osemiconductor material.

As the metal oxide semiconductor active layer 402 is of Cu₂O, eventhough electrode material adopts Cu metal, the metal oxide semiconductoractive layer 402 will not be sensitive to the diffusion effect of the Cumetal.

Moreover, for instance, as illustrated in FIGS. 1a and 1b , the metaloxide semiconductor active layer 402, the source electrode 501 and thedrain electrode 502 are arranged in the same layer; and the sourceelectrode 501 and the drain electrode 502 are of a Cu metallic material.

As Cu₂O semiconductors may be formed by the electrochemical reaction onCu metal, the pattern of the source electrode 501, the pattern of thedrain electrode 502 and the pattern disposed between the pattern of thesource electrode 501 and the pattern of the drain electrode 502, namelythe above-mentioned first pattern 401, which are of a Cu metallicmaterial and arranged in the same layer, may be formed by a singlepatterning process; subsequently, the Cu metallic material in the firstpattern 401 may be converted into Cu₂O semiconductor material byelectrochemical reaction; and hence the first pattern 401 is formed intothe metal oxide semiconductor active layer 402.

Herein, after the first pattern 401 is formed, as the process of formingthe metal oxide semiconductor active layer 402 by the first pattern 401only needs the electrochemical reaction, the step of forming the patternof the source electrode 501, the pattern of the drain electrode 502 andthe first pattern by a single patterning process is namely that thesource electrode 501, the drain electrode 502 and the metal oxidesemiconductor active layer 402 are formed by a single patterningprocess. Therefore, compared with the mode of forming the sourceelectrode 501, the drain electrode 502 and the metal oxide semiconductoractive layer 402 by two patterning processes, the embodiment of thepresent invention reduces the number of the patterning processes.

On this basis, compared with the mode of additionally forming an etchbarrier layer in order to avoid the influence on the metal oxidesemiconductor active layer 402 when the source electrode 501 and thedrain electrode 502 are etched, in the embodiment of the presentinvention, as the first pattern for forming the metal oxidesemiconductor active layer 402, the pattern of the source electrode 501and the pattern of the drain electrode 502 are formed at the same time,the etch barrier layer is not required to be formed, and hence thenumber of the patterning processes can be further reduced. In addition,in the mode of forming the etch barrier layer, as the source electrode501 and the drain electrode 502 must be connected with the metal oxidesemiconductor active layer 402, the etch barrier layer may include afirst through hole through which the source electrode 501 and the metaloxide semiconductor active layer 402 are connected and a second throughhole through which the drain electrode 502 and the metal oxidesemiconductor active layer 402 are connected. Moreover, the firstthrough hole and the second through hole cannot be too close indistance, thus the size of the TFT is limited. As the embodiment of thepresent invention has no limit in this aspect, the size of the TFT canbe reduced, and hence the demand on high PPI can be satisfied.

Moreover, for instance, the gate insulating layer 30 at least includes aTiO₂ and/or Al₂O₃ layer in contact with the metal oxide semiconductoractive layer 402, the source electrode 501 and the drain electrode 502.

As TiO₂ or Al₂O₃ can be well bonded with Cu metal, the TiO₂ or Al₂O₃layer is arranged on, for instance, the upmost layer of the gateinsulating layer 30, so that the subsequently formed Cu metal film canbe well bonded with the substrate, and hence the formed metal oxidesemiconductor active layer 402 of the Cu₂O material and the sourceelectrode 501 and the drain electrode 502 of the Cu metallic materialhave more stable performance.

The embodiment of the present invention further provides an arraysubstrate, which comprises the foregoing TFTs.

For instance, the array substrate provided by the embodiment of thepresent invention may be an array substrate of an LCD. In this case, asillustrated in FIG. 3, the array substrate may further comprise pixelelectrodes 801 electrically connected with the drain electrodes 502.

Moreover, as illustrated in FIG. 4, the array substrate may furthercomprise common electrodes 802 and a passivation layer.

Of course, the array substrate provided by the embodiment of the presentinvention may also be an array substrate of an OLED display. In thiscase, for instance, as illustrated in FIG. 5, the array substratefurther comprises an anode 901 electrically connected with the drainelectrode 502, an organic material function layer 902 disposed on theanode 901, and a cathode 903 disposed on the organic material functionlayer 902.

As for the array substrate of the OLED display, one sub-pixel thereingenerally includes two TFTs, namely a switching TFT and a driving TFT; agate electrode 20 of the switching TFT is electrically connected with agate line; a source electrode 501 of the switching TFT is electricallyconnected with a data line; a drain electrode 502 of the switching TFTis electrically connected with a gate electrode 20 of the driving TFT; asource electrode 501 of the driving TFT is electrically connected with apower line; and a drain electrode 502 of the driving TFT is electricallyconnected with the anode 901.

Herein, it should be noted that no matter the TFT is a switching TFT ora driving TFT, the forming method thereof may adopt the foregoing methodfor manufacturing the TFT.

The embodiment of the present invention further provides a displayapparatus, which comprises the foregoing array substrate.

For instance, when the array substrate may be an array substrate of anLCD, the display apparatus further comprise an opposing substrate (e.g.,a color filter (CF) substrate) and a liquid crystal layer disposedbetween the array substrate and the opposing substrate.

When the array substrate is an array substrate of an OLED display, thedisplay apparatus further comprise a package substrate.

The display apparatus provided by the embodiment of the presentinvention may be: any product or component with display function such asan LCD panel, e-paper, an OLED panel, an LCD TV, an LCD, a digitalpicture frame, a mobile phone, a tablet PC, and the like.

The foregoing is only the preferred embodiments of the present inventionand not intended to limit the scope of protection of the presentinvention. The scope of protection of the present invention should bedefined by the appended claims.

The application claims priority of the Chinese patent application No.201510044070.1, filed on Jan. 28, 2015, the disclosure of which isincorporated herein by reference as part of the application.

1. A method for manufacturing a thin-film transistor (TFT), comprising:forming a gate electrode, a gate insulating layer, a metal oxidesemiconductor active layer, a source electrode and a drain electrode ona substrate, in which forming of the metal oxide semiconductor activelayer includes: forming the metal oxide semiconductor active layer byelectrochemical reaction.
 2. The method according to claim 1, whereinthe metal oxide semiconductor active layer is of a Cu₂O semiconductormaterial.
 3. The method according to claim 2, wherein the metal oxidesemiconductor active layer of the Cu₂O semiconductor material is formedby the electrochemical reaction on a Cu metallic material.
 4. The methodaccording to claim 3, wherein forming of the metal oxide semiconductoractive layer of the Cu₂O semiconductor material by the electrochemicalreaction on the Cu metallic material includes: placing a substrateprovided with a first pattern of the Cu metallic material in water andelectrifying the first pattern, whereby the Cu metallic material issubjected to electrolytic reaction with the water to form the Cu₂Osemiconductor material, and the first pattern is formed into the metaloxide semiconductor active layer.
 5. The method according to claim 4,further comprising: before the substrate provided with the first patternis placed in water, forming the first pattern of the Cu metallicmaterial in an active region by a patterning process.
 6. The methodaccording to claim 5, wherein a pattern of the source electrode, apattern of the drain electrode and the first pattern, which are arrangedin a same layer, are formed by a single patterning process.
 7. Themethod according to claim 6, wherein forming of the pattern of thesource electrode, the pattern of the drain electrode and the firstpattern, which are arranged on the same layer, by the single patterningprocess includes: forming a Cu metal film on the substrate; and formingthe pattern of the source electrode, the pattern of the drain electrodeand the first pattern disposed in the active region by performing ahalf-tone mask process on the Cu metal film, in which except the firstpattern, other patterns made from the Cu metal film are covered byphotoresist before electrochemical reaction is performed.
 8. The methodaccording to claim 7, wherein forming of the pattern of the sourceelectrode, the pattern of the drain electrode and the first patterndisposed in the active region by performing the half-tone mask processon the Cu metal film includes: forming photoresist on the substrateprovided with the Cu metal film; forming photoresist-completely-retainedportions, a photoresist-semi-retained portion andphotoresist-completely-removed portions after performing exposure anddevelopment on the substrate provided with the photoresist via ahalf-tone mask or a gray-tone mask, in which thephotoresist-completely-retained portions correspond to regions of thepattern of the source electrode and the pattern of the drain electrodethat are to be formed; the photoresist-semi-retained portion correspondsto the active region; and the photoresist-completely-removed portionscorrespond to regions that are not to be provided with Cu metal patternsand other regions except the active region; forming the pattern of thesource electrode, the pattern of the drain electrode and the firstpattern disposed in the active region by removing the Cu metal filmcorresponding to the photoresist-completely-removed portions by anetching process; and removing the photoresist in thephotoresist-semi-retained portion by an ashing process.
 9. The methodaccording to claim 1, wherein forming of the metal oxide semiconductoractive layer includes: forming a metal film on the substrate; formingthe first pattern disposed in the active region by performing a singlepatterning process on the metal film; and forming the first pattern intothe metal oxide semiconductor active region by the electrochemicalreaction.
 10. The method according to claim 1, wherein forming of themetal oxide semiconductor active layer includes: forming a film of ametallic material on the substrate; converting the film of the metallicmaterial into a film of the metal oxide semiconductor material by theelectrochemical reaction; and removing the film of the metal oxidesemiconductor material in the region other than the active region by apatterning process to form the metal oxide semiconductor active layer inthe active region.
 11. The method according to claim 1, wherein the gateinsulating layer at least includes a TiO₂ and/or Al₂O₃ layer in contactwith the metal oxide semiconductor active layer.
 12. A thin-filmtransistor (TFT), comprising a gate electrode, a gate insulating layer,a metal oxide semiconductor active layer, a source electrode and a drainelectrode, wherein the metal oxide semiconductor active layer is formedby electrochemical reaction.
 13. The TFT according to claim 12, whereinthe metal oxide semiconductor active layer is of a Cu₂O semiconductormaterial.
 14. The TFT according to claim 13, wherein the metal oxidesemiconductor active layer, the source electrode and the drain electrodeare arranged in a same layer, in which the source electrode and thedrain electrode are of a Cu metallic material.
 15. The TFT according toclaim 11, wherein the gate insulating layer at least includes a TiO₂and/or Al₂O₃ layer in contact with the metal oxide semiconductor activelayer, the source electrode and the drain electrode.
 16. An arraysubstrate, comprising the TFT according to claim
 12. 17. A method formanufacturing an array substrate, comprising forming a TFT on asubstrate, wherein the TFT is formed with the method according toclaim
 1. 18. A display apparatus, comprising the array substrateaccording to claim
 16. 19. The method according to claim 2, whereinforming of the metal oxide semiconductor active layer includes: forminga metal film on the substrate; forming the first pattern disposed in theactive region by performing a single patterning process on the metalfilm; and forming the first pattern into the metal oxide semiconductoractive region by the electrochemical reaction.
 20. The method accordingto claim 3, wherein forming of the metal oxide semiconductor activelayer includes: forming a metal film on the substrate; forming the firstpattern disposed in the active region by performing a single patterningprocess on the metal film; and forming the first pattern into the metaloxide semiconductor active region by the electrochemical reaction.